Adsorbate modification of electronic nonadiabaticity: H atom scattering from p(2 × 2) O on Pt(111)

Abstract

We report inelastic differential scattering experiments for energetic H and D atoms colliding at a Pt(111) surface with and without adsorbed O atoms. Dramatically, more energy loss is seen for scattering from the Pt(111) surface compared to p(2 × 2) O on Pt(111), indicating that O adsorption reduces the probability of electron–hole pair (EHP) excitation. We produced a new full-dimensional potential energy surface for H interaction with O/Pt that reproduces density functional theory energies accurately. We then attempted to model the EHP excitation in H/D scattering with molecular dynamics simulations employing the electronic density information from the Pt(111) to calculate electronic friction at the level of the local density friction approximation (LDFA). This approach, which assumes that O atoms simply block the Pt atom from the approaching H atom, fails to reproduce experiment due to the fact that the effective collision cross section of the O atom is only 10% of the area of the surface unit cell. An empirical adiabatic sphere model that reduces electronic nonadiabaticity within an O–Pt bonding length scale of 2.8 Å reproduces experiment well, suggesting that the electronic structure changes induced by chemisorption of O atoms nearly remove the H atom’s ability to excite EHPs in the Pt. Alternatives to LDFA friction are needed to account for this adsorbate effect.

Electronically Nonadiabatic H Atom Scattering from Low Miller Index Surfaces of Silver

“…A series of scattering experiments have been performed in which high-energy H atoms were shot onto fcc(111) metal surfaces. In combination with electronically nonadiabatic molecular dynamics (MD) simulations, it was demonstrated that the energy transfer from the projectile to the metallic surface is dominated by electronic excitations. − When the metal surface is exchanged with a noble-gas surface, however, the excess energy is completely taken up by the lattice, and surface penetration was identified to be the first step in adsorption . Regardless of the recent advance on H atom scattering studies, the role of the surface structure has not been the subject of investigation yet.…”

Dissipative tunneling rates through the incorporation of first-principles electronic friction in instanton rate theory. II. Benchmarks and applications

“…While the former depends mainly on the metal at hand, the latter is affected by both the impurity and the metal. 59 We analyzed the atomic projected DOS (see Sec. III C in the supplementary material) and confirmed that Pd and Pt are, at the same time, the systems that present the largest electronic friction values and the highest DOS at the Fermi level among the transition metals.…”

Dissipative Tunneling Rates through the Incorporation of First-Principles Electronic Friction in Instanton Rate Theory II: Benchmarks and Applications

“…11 via the Fermi-Dirac factors, the latter contributes via the strength of the nonadiabatic coupling. While the former depends mainly on the metal at hand, the latter is affected by both the impurity and the metal 63 . We analyzed the atomic projected DOS (see section III C in the SI) and confirmed that Pd and Pt are, at the same time, the systems that present the largest electronic friction values and the highest DOS at the Fermi level among the transition metals.…”